19 July 2002

Fertility proofs are good news for UKindustry

By Richard Allison

THE continuing decline in first service pregnancy rates could be halted by the launch of new bull proofs incorporating cow fertility early next year, says one researcher.

Selecting bulls for milk yield has inadvertently led to producers selecting against cow fertility, University of Nottingham researcher Tony Flint will tell the Nottingham Cattle Fertility Conference in September. "But fertility proofs would allow dairy bulls to be selected which improve milk yield and produce fertile cows."

Fertility proofs have been available in some European countries for nearly 15 years, resulting in a slower decline in cow fertility. Despite this, no fertility index has been published in the UK, says Prof Flint.

"But this is set to change early in 2003 when a Sustainable Livestock Production LINK-funded project across three research centres publishes the first PLI plus fertility bull proofs."

He believes one reason for the slow arrival of a UK fertility index is unreliable information. In Scandinavian countries, data is of high quality because recording of fertility information is a legal requirement.

"The last year has been spent cleaning UK data before being used to calculate proofs. Cows with impossibly long or short calving intervals were removed."

Another problem is the low heritability of traits, including calving interval and calving to first insemination, because they are strongly influenced by management. "Calving interval can be extended for high yielding cows, while first insemination dates are often not recorded giving the impression that cows start cycling later in lactation."

Fortunately, new data from a parallel study was available on the correlation between fertility and both milk yield and body condition score. "We have been able to improve the accuracy of management-based data using correlated yield and condition score information to calculate breeding values."

Prof Flint believes the resulting proofs will be as reliable as those published in other EU countries.

"The project also faced the problem of obtaining pedigree information from different databases. The databases use different ways to record cow identity and contain many errors, which need to be removed. But UK fertility data recording is starting to get better."

Unlike calving interval and insemination dates, milk progesterone levels are less influenced by management leading to a higher heritability of fertility, up to 25%. The second phase of the project will include progesterone data in the proofs to speed up progress. The value of progesterone data is currently being investigated in a new study.

Prof Flint envisages that the consortium will continue to calculate the index until the end of 2004. Then the calculation method will be passed to Milk Evaluations, a subsidiary of MDC.

But the indexs impact on the fertility of UK dairy cows depends heavily on accessibility of the information to breeding companies and producers. In addition, gains in fertility will take some time to become fully evident, as breeding companies have already selected bulls to be marketed over the next five years without the index, he says.

&#8226 The Nottingham Cattle Fertility Conference will be held on Sept 5 at Sutton Bonnington, Leics. Further details are available from Marilyn Prentice (01159-516061; fax 01159-516069). The cost is £35, including buffet lunch and a copy of the proceedings. &#42

FERTILITY INDEX

&#8226 Data reliability.

&#8226 Reduce fertility decline.

&#8226 Available next year.

CONFERENCE PROGRAMME

Morning Session

&#8226 Tony Flint, University of Nottingham – Introducing the UK fertility index.

&#8226 Maurice Boland, University College Dublin – Impact of current management practices on embryo survival in the modern dairy cow.

&#8226 Will Christie, Paragon Vet Group – Ovum pick-up and embryo transfer.

&#8226 Marco Winters, Cogent – Semen Sexing.

Afternoon Session

Alistair Smith, Overflow – Practical application of developing techniques.

&#8226 Roger Blowey, Wood Vet Group – DIY AI training and supervision.

&#8226 Workshop and question time.

&#8226 Data reliability improved.

&#8226 Can reduce fertility decline.

&#8226 Available next year.

Suffering poor fertility results?Help is on the way with a new index now the problems with reliability of UKdata have been overcome, says Tony Flint.

Morning Session

&#8226 Tony Flint, University of Nottingham – Introducing the UK fertility index.

&#8226 Maurice Boland, University College Dublin – Impact of current management practices on embryo survival in the modern dairy cow.

&#8226 Will Christie, Paragon Vet Group – Ovum pick-up and embryo transfer.

&#8226 Marco Winters, Cogent – Semen Sexing.

Afternoon Session

&#8226 Alistair Smith, Overflow – Practical application of developing techniques.

&#8226 Roger Blowey, Wood Vet Group – DIY AI training and supervision.

&#8226 Workshop and question time.